Laboratory methods for rapid identification of Clostridium difficile: a comparison of the test efficiency
LI Chun-hui;LIU Si-di;TANG Sheng-hong;DUAN Ju-ping;WU An-hua;Hospital Infection Control Center,Xiangya Hospital of Central South University;
Objective To identify the fastest and most accurate method among three laboratory methods for identification of Clostridium difficile. Methods 248 stool specimens from 136 ICU inpatients during June and November2013 were collected and cultured for anaerobic bacteria for 24 hours and 48 hours respectively. DNA was extracted from the stool specimens for tcd B gene detection. Based on the result of 48-hour culture method,the sensitivity,specificity and positive and negative predictive values of 24-hour culture and those of PCR amplification of tcd B gene were evaluated. Results Among the 136 ICU patients with diarrhea,11 patients with a total of 12 specimens were found positive for Clostridium difficile after 48 hours. The rate of Clostridium difficile infection( CDI) was8. 09%( 11 /136); 4. 84%( 12 /248) of the stool specimens were found positive for Clostridium difficile. The sensitivity,specificity,positive predictive value and negative predictive value were 75. 00%,100%,100% and98. 74% for the 24-hour culture method and 83. 33%,99. 15%,83. 33%,99. 15% for tcd B gene PCR amplification method. Conclusion The stool DNA extraction for tcd B testing is the most rapid method with higher sensitivity and specificity. The 48-hour culture medthod takes more time but the results are consistent and reliable,and the strains can be preserved for following experiments. The 24-hour culture method is simple and takes less time,but may miss some positive cases.